Various proposed shaking solutions are known from the prior art.
U.S. Pat. No. 4,128,344 proposes a device for shaking a product contained in test tubes. The device comprises a drive unit with a planetary gear train that rotates the test tube, particularly about its main axis, in order to shake the contents.
Patent FR1529066 concerns a shaking device comprising tubes arranged on a turntable. The turntable is rotatable about a main axis. The rotation of the turntable shakes the tubes and their contents.
U.S. Pat. No. 3,980,227 relates to a shaking device having a central axis and a plate which rotates about an axis inclined relative to the central axis, in order to agitate containers. However, in addition to the complexity in implementing this device, the mixing is unsatisfactory.
Such embodiments allow a mechanical and reproducible shaking of tubes and their content. These solutions are unsuitable, however, for shaking content consisting of a material in powder form and a liquid product within a rigid container having a capacity of less than a liter, in a manner that is comparable to manual shaking. There is therefore a need for a device that can perform shaking comparable to manual shaking, which is simple to implement and can be used in particular for conducting quality tests, for example such as quality tests on flour samples according to the 56-11 method defined by AACC International.
For this purpose, the device for shaking, within a rigid container, content comprising a material in powder form and a liquid product, for the purpose of conducting a test on the shaken content, said container having a capacity of less than one liter and able to hold an amount of content suitable for conducting the test according to the invention, comprises:                a frame,        a first plate, assembled directly or indirectly to the frame,        a second plate assembled indirectly to the frame, arranged close to the first plate and movable relative to the frame and to the first plate, and        a drive unit suitable for moving the second plate relative to the frame and to the first plate,and is characterized in that:        the container is carried by the second plate and is movably mounted relative to the second plate,        the first plate comprises a stop, said stop being arranged near to and facing the container, the stop being fixedly mounted on the first plate, and        the second plate is moved relative to the first plate by means of the drive unit, in an alternating and repeating translational and/or rotational motion between a proximal position and a distal position, so as to move the container relative to the second plate and cause a series of impacts between the container and the stop in order to achieve a non-periodic shaking of the container by the alternating and repeating motion of the second plate.        
With this embodiment, the shaking that results is non-periodic or irregular and reproduces a manual shaking. Among other things, such irregular mixing allows blending to complete homogenization. In addition, the device can be implemented simply and can be associated with other devices: for example it can be associated with a centrifuge in order to conduct tests and assays.
In one embodiment, the second plate has a plate axis, and the container is assembled to the second plate and is rotatable about the plate axis. The relative rotational motion of the container in relation to the second plate limits the damage that could result from the series of impacts between the container and the stop and increases the irregularity of the shaking.
According to an additional embodiment, the container is a test tube and comprises a rigid hollow body extending longitudinally along a container axis between a first end and a second end, the second end defining an opening for the filling thereof. The container has an elongate shape which allows specific kinematics, thereby increasing the irregularity of the shaking.
According to an additional embodiment, the plate axis is located substantially nearer to the first end or to the second end; the plate axis is not equidistant from the first end and the second end. The path traveled by the container end furthest from the plate axis is longer than the path traveled by the container end closest to the plate axis.
In one embodiment, the stop is a rigid stop and the impact between the container and the stop is an elastic or substantially elastic collision. This elastic or quasi-elastic collision causes the container to rebound from the stop. There is substantially no permanent deformation of the container or of the stop. More specifically, the rigid container can rebound from the stop, creating movement of the rigid container that is not directly controlled by the drive unit.
In one embodiment, the drive unit moves the second plate in translation with respect to the first plate, between the proximal position and the distal position, along a shaking axis in a first direction and in a second direction that is opposite the first direction. The movement of the second plate alternates between translational motion in a first direction and translational motion in a second direction. The translational motion of the second plate relative to the first plate in one direction then the other is easy to implement, for example by means of a drive unit such as a motor.
In one embodiment, the shaking axis is orthogonal to the plate axis. The sliding motion along the shaking axis (also known as the driving motion) causes rotational movement of the container about the plate axis (also known as the driven motion), and the orthogonality of the shaking axis with the plate axis allows optimizing the amplitude of the driven motion.
In one embodiment, the course of the second plate between the proximal position and the distal position is between 10 millimeters and 50 millimeters in length, preferably about 35 millimeters. For a container having a capacity of less than a liter, a course of between 10 millimeters and 50 millimeters in length and preferably about 35 mm is optimal for satisfactory blending. The reduced size of this stroke allows the shaking device to be compact.
In one embodiment, the drive unit moves the second plate in a periodic motion at a frequency of between 1 and 10 Hertz, preferably at a frequency of about 5 Hertz. The periodic translational motion of the second plate is repeated several times per second. For example, the second plate moves at a frequency of about five oscillations per second. The range of oscillation frequencies is provided by control elements which are readily available commercially and which correspond to the recommended frequency for the manual shaking method used for flour determinations according to method 56-11 of the AACC International.
In one embodiment, the second plate has a second stop limiting the angular travel of the container about the plate axis. The second stop allows the device to be more compact by reducing the possible angular travel of the container about the plate axis. In addition, a second impact can be brought about between the second stop and the container. The second impact can amplify the irregularity of the container movement.
According to one embodiment, the pivoting of the container about the plate axis has an angular travel of less than 120°, preferably about 60°. With such angular travel, shaking similar to manual shaking can be achieved. This angular travel is measured, for example, between a first position of the container when it is in contact with the stop of the first plate, and a second position of the container when it is in contact with the second stop.
In one embodiment, the container is detachably associated with the second plate, the second plate comprises a notch, and the shaking device further comprises a connecting member which connects the container to the second plate, said connecting member cooperating with the notch and being assembled to the second plate and rotatable relative to the second plate about the plate axis, said connecting member comprising:                a first portion for detachably receiving the container,        a second portion extending along the plate axis, allowing rotation of the container about the plate axis relative to the second plate.        
In one embodiment, the shaking device comprises a plurality of containers, the first plate defines a central axis and the second plate defines a second central axis with the first and second axes being coaxial, the first plate comprises the same number of stops as the number of containers, and each container is associated with a stop. It is thus possible to shake multiple containers simultaneously, which reduces testing and assay time. In addition, the shaking is similar for all the containers.
A second aspect of the invention relates to the use of the shaking device as described above, for the purpose of measuring the absorption capacity of a flour sample for a solvent.
A third aspect of the invention relates to a method for shaking a container, comprising the steps of:                having a shaking device as described above,        partially filling the container with a material in powder form and with a liquid product,        setting the second plate in motion by means of the drive unit in an alternating and repeating translational and/or rotational motion so as to move the container relative to the second plate and cause a series of impacts between the rigid container and the stop in order to achieve a non-periodic shaking of the container by the alternating motion of the second plate,        stopping the motion of the second plate.        
According to one embodiment of the method, the steps of setting the second plate in motion and stopping the motion of the second plate are repeated.
According to one embodiment, the method further comprises a step of placing the container on the second plate and a step of removing the container from the second plate.